Greenhouses require airflow to maintain a healthy environment to grow plants. Typically this airflow has been provided by vents that are open to the outside environment. However, this allows exposure of the plants to airborne contaminants, which can be harmful to immature plants. Where plants are grown for shipping to a different geographic region, this could lead to the shipping of undesirable plant disease vectors.
An air filtering system for a greenhouse air intake duct could reduce this problem. However, existing systems often require specialized installation and are expensive. An inexpensive in-line filtering system that could be easily installed into existing ductwork would be an improvement in the art.